Disclosed herein is a support structure for a load measurement sensor, and particularly, to a support structure for a load measurement sensor which is supported in the state where an extension portion extending from a sensor body is positioned at a side portion of the sensor body.
With a view to improving the safety of a passenger or the comfort thereof when the passenger sits on a seat, there is proposed a technique of controlling an operation of a device around a vehicle seat in response to the weight of the sitting passenger.
In such a technique, in order to detect the weight of the sitting passenger, a load measurement sensor is generally disposed below the vehicle seat on which the passenger sits.
The installation position of the load measurement sensor is generally located below the vehicle seat. Then, for example, there is a known configuration in which a load measurement sensor is provided between a seat frame constituting a vehicle seat and a slide rail provided to slide the vehicle seat in the front-to-back direction (see Japanese Patent Document No. 4205028B1 (“the '028 Reference”)).
The '028 Reference discloses, as illustrated in FIG. 37, a configuration in which a load measurement sensor 130 (which it describes as a “load sensor”) is provided above an upper rail 112 (which it describes as a “slider”) sliding on a lower rail 111 (which it describes as a “rail body”) attached to a vehicle body floor and a seat frame 101 is disposed above the load measurement sensor 130. Furthermore, FIG. 37 is a partial perspective view illustrating a vehicle seat which adopts the support structure for the load measurement sensor according to the related art.
Then, as illustrated in FIG. 38, in order to fix the load measurement sensor 130 to the seat frame 101, a shaft portion 131 (which it describes as a “male screw”) is provided, and the shaft portion 131 is disposed so that its axial direction becomes the vertical direction. In recent years, in order to improve the convenience of the passenger who gets in and out of the vehicle or the design of the vehicle, a technique is demanded which lowers the height of the vehicle seat. However, in the case where the load measurement sensor 130 is provided with such a technique, the seat frame 101 is disposed so that the seat frame 101 increases in height by the height of the load measurement sensor 130, which causes a problem in which the height of the vehicle seat increases. FIG. 38 is a cross-sectional view illustrating the support structure for the load measurement sensor according to the related art.
On the other hand, there is proposed a technique in which the shaft portion is disposed so that the axial direction of the shaft portion for attaching the load measurement sensor thereto is not set as the vertical direction, but is set as the horizontal direction (see Japanese Patent Document No. 2010-42809A (“the '809 Reference”)).
In the '809 Reference, the load measurement sensor (which it describes as a “load detection sensor”) is provided so that the axial direction becomes the horizontal direction and the load measurement sensor is disposed to be included in the height range of the seat frame. For this reason, the height of the vehicle seat may be lowered compared to the technique of the '028 Reference.
On the other hand, there is a known load measurement sensor which includes a deformation portion deformed by receiving a load, in which the deformation portion is provided as a detection portion for detecting the load. When such a sensor receives the load from the seat while being supported so that the axial direction of the shaft portion follows the horizontal direction, the deformation portion is deformed to be curved inward in the radial direction of the shaft portion by receiving the load. Then, the load is measured based on the deformation amount of the deformation portion. However, in the load measurement sensor, when a biased load is applied to the load measurement sensor due to the influence of the passenger's seating posture or seating position, the deformation portion may be excessively deformed. In such a state, there is a possibility that the load may not be normally measured.
Therefore, various embodiments of the invention are made in view of the above-described problems, and provide a support structure for a load measurement sensor capable of measuring a load by a deformation amount of a deformation portion and of disposing a load measurement sensor at a position where a load is normally and stably measured by inhibiting an excessive deformation.
Further, in order to support the load measurement sensor at a predetermined position, an insertion hole may be formed in a sensor supporting member and a shaft portion may be inserted into the insertion hole. On the other hand, there is a possibility that the load measurement sensor in which the shaft hole is inserted into the insertion hole may rotate about the shaft portion with respect to the member provided with the insertion hole. By the relative rotation of the load measurement sensor, the position of the load detection surface provided at a predetermined portion of the sensor changes in the rotation direction.
Then, the direction of the load detection surface with respect to the load changes by a positional change in the load detection surface, which adversely affects the load measurement precision of the load measurement sensor. For this reason, there is a need to inhibit the rotation of the load measurement sensor after the shaft portion is inserted into the insertion hole. Here, when inhibiting the relative rotation of the load measurement sensor, there is a concern that a local force (contact pressure) may act on the member provided with the insertion hole or the load measurement sensor and the shaft portion of the load measurement sensor may be cut out so that the member provided with the insertion hole is deformed. In such a state, the load measurement precision is adversely affected and the load is not easily and appropriately measured.
Therefore, various embodiments of the invention further provide a support structure for a load measurement sensor capable of holding a load measurement sensor at a position where a load may be accurately measured.
Further, as described above, there is the known load measurement sensor which includes the deformation portion deformed by receiving the load from the seat, but in such a sensor, there is a concern that a biased load may be applied to the deformation portion when the load is applied from the seat.
Therefore, various embodiments of the invention further provide a support structure for a load measurement sensor capable of inhibiting a biased load from being applied to a load detection portion of a sensor body.
In addition, when the load measurement sensor is moved by the load transmitted from the seat to the load measurement sensor and the deformation portion is deformed, if the load is not appropriately transmitted to the deformation portion, there is a possibility that the deformation of the deformation portion may be disturbed. For this reason, there is a possibility that the load may not be appropriately detected by the deformation portion even when the load is input from the seat.
Therefore, various embodiments of the invention further provide a support structure capable of reliably transmitting a load input from a seat to a load measurement sensor to accurately detect the input load.